What happens if I withdraw Bitcoin from Coinbase?

I'm curious to know, what exactly happens when I withdraw Bitcoin from Coinbase? I've been using the platform for some time and have accumulated a decent amount of BTC, but I'm now considering moving it to a cold storage wallet for security purposes. What's the process like? Are there any fees involved? How long does it typically take for the transaction to be confirmed? And what should I do to ensure the withdrawal is as smooth and secure as possible? Understanding these details is crucial for me to make an informed decision.